English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Plus monthly

Global: Zendy Tools annual

Global: Zendy Tools monthly

Global: Zendy Free Plan

The objective of this work is to investigate the challenges encountered inScale-Resolving Simulations (SRS's) of turbulent wake flows driven byspatially-developing coherent structures. SRS's of practical interest areexpressly intended for efficiently computing such flows by resolving only themost important features of the coherent structures and modelling the remainderas stochastic field. The success of SRS methods depends upon three importantfactors: i) ability to identify key flow mechanisms responsible for thegeneration of coherent structures; ii) determine the optimum range ofresolution required to adequately capture key elements of coherent structures;and iii) ensure that the modelled part is comprised nearly exclusively offully-developed stochastic turbulence. This study considers the canonical caseof the flow around a circular cylinder to address these three key issues. It isfirst demonstrated using experimental evidence that the vortex-sheddinginstability and flow-structure development involves four important stages. Aseries of SRS computations of progressively increasing resolution areperformed. An a priori basis for locating the origin of the coherent structuresdevelopment is proposed and examined. The criterion is based on the fact thatthe coherent structures are generated by the Kelvin-Helmholtz (KH) instability.The most important finding is that the key aspects of coherent structures canbe resolved only if the effective computational Reynolds number exceeds thecritical value of the KH instability in laminar flows. Finally, a quantitativecriterion assessing the nature of the unresolved field based on the strain-rateratio of mean and unresolved fields is examined. The two proposed conditionsand underlying rationale offer a quantitative basis for develop "good practice"guidelines for SRS of complex turbulent wake flows with coherent structures.

Challenges in Modelling and Simulation of Turbulent Flows with Spatially-Developing Coherent Structures